Cross Bore Inspections Explained

Cross Bore Inspections Explained

A historic university in California turned to GPRS when they needed to mitigate the risk of cross bores during a directional boring project.

New telecommunication lines and electrical conduit were being installed all throughout the main campus of Pepperdine University in Malibu, California. To ensure the safe installation of those lines, GPRS Project Manager David Castro performed video pipe inspection services to locate and map the university’s wastewater infrastructure.

A private research university founded in 1937 by entrepreneur George Pepperdine, Pepperdine University opened its current main campus located near Malibu in 1972. Today, that campus consists of 830 acres overlooking the Pacific Ocean and Pacific Coast Highway.  

Castro conducted professional sewer inspection services to locate and map the campus’ intricate wastewater system that runs too deep for ground penetrating radar (GPR) scanners to detect.

A GPRS Project Manager pulls a sewer inspection rover out of the back of a van.
GPRS Project Managers conduct video pipe inspection services to mitigate risks to your wastewater infrastructure.

“Our client received as-builts from the university,” Castro explained. “We were called in to assist with the locating of storm and sewer lines, and to confirm what was on site and what was not. There were a lot of abandoned sections of pipe due to a newer system being installed at some point.”

GPRS’ client was installing new communication and electrical lines using a trenchless technology known as directional boring. Also called horizontal directional drilling, this process involves boring into the ground at a low angle with a directional drill bit to create a path for a new utility.  

One of the primary benefits of directional boring can also be its biggest drawback: by not having to trench to install a new line, you avoid significant surface disruption, but also run the risk of causing cross bores.

Cross bores are inadvertent intersections of utilities that most commonly occur when directional boring activities are undertaken prior to, or without proper inspection and mapping of underground infrastructure. The consequences of cross bores vary depending on the type of utilities involved; if a sewer line has been compromised, you run the risk of service interruptions, inflow/infiltration, or contaminated soil. If a gas line has been bored through, you could be a spark away from a catastrophic explosion.

The Cross Bore Safety Association estimates that there are at least one million undetected cross bores ridding the United States’ buried infrastructure. This is why GPRS recommends all municipalities and facilities require cross bore inspections of their storm and sewer systems both before and after any directional boring occurs, so that they can avoid adding to this troubling statistic.

These inspections are mandatory in many places across the country, including Fremont, California, where GPRS Project Managers uncovered ten cross bores when scanning before and after the installation of fiber optic cable throughout the city. By mandating these inspections, you ensure that these ticking time bombs can be remediated before it’s too late.

A yellow utility line is cross bored through a PVC pipe.
Cross bores like this riddle the United States’ buried infrastructure. You can prevent new cross bores from occurring within your infrastructure by requiring video pipe inspections of your sewer system both before and after directional boring occurs.

How GPRS Performs Cross Bore Inspections

GPRS’ sewer scope services help prevent cross bores by providing you with accurate, actionable data about your wastewater infrastructure.

Using an array of remote-controlled sewer inspection rovers, our Project Managers evaluate your sewer and stormwater lines for clogs, cross bores, structural faults, and damages, and other defects. These rovers are equipped with sondes: instrument probes that allow us to ascertain the precise location of the rover from the surface. In this way, we can map your lines at the same time we’re investigating them.

When we’re finished, you receive a detailed, NASSCO-certified report that ranks any issues found by severity and includes video and photographic evidence of the defects, so you know where to dig and what needs addressing first.

Industry-leading Training

The GPRS process for sewer inspections is supported by both NASSCO, the National Association of Sewer Service Companies, and SIM, or Subsurface Investigation Methodology.

NASSCO provides training on the most advanced, non-destructive methods for detecting and reporting anomalies within buried sewer lines. GPRS VPI Project Managers complete NASSCO’s Pipeline Assessment Certification Program (PACP), Lateral Assessment Certification Program (LACP) and Manhole Assessment Certification Program (MACP) to learn how to consistently and accurately assess the condition of pipelines, laterals, and manholes.

SIM is the industry-leading training process for utility locating, concrete scanning, video pipe inspections, and leak detection. All GPRS Project Managers must become SIM certified before entering the field, which means completing a minimum of 320 hours of field training and 80 hours of classroom training. During both the in-field and in-classroom instruction, the PMs encounter real-world scenarios that prepare them for anything they may encounter on a job.

By adhering to the standards set forth by both NASSCO and SIM, our Project Managers provide you with consistently excellent sewer inspections, so you always know you’re receiving the highest level of service from a sewer inspection company you can trust.

From skyscrapers to sewer lines, GPRS Intelligently Visualizes The Built World® to keep your projects on time, on budget, and safe.  

What can we help you visualize? Click the links below to schedule a service or request a quote today!

Frequently Asked Questions

How do you inspect a sewer system?

GPRS recommends hiring a professional sewer inspection company like us to inspect your sewer system, both for regular maintenance purposes, and before and after directional boring activities take place near your wastewater infrastructure.

These inspections involve the sewer inspection technician sending remote-controlled rovers into your lines to inspect them for clogs, cracks, and other defects that could compromise their integrity and lead to issues such as service interruptions.

NASSCO-certified sewer inspectors will leave you with detailed reports of any issues found, with those problems ranked by severity and identified with both video and photographic evidence to help you in your maintenance and repair planning.

Are sewer scopes worth it?

Purchasing sewer scopes and other inspection devices is too costly and impractical for most, and the training required to properly operate this equipment is an additional cost and time commitment. That’s why we recommend hiring a professional sewer inspection company near you to complete the work you need to maintain your wastewater infrastructure.

What size pipes can GPRS inspect?

Our elite VPI Project Managers have the capabilities to inspect pipes from 2” in diameter and up.

Yes, our SIM- and NASSCO-certified Project Managers use VPI technology equipped with sondes, which are instrument probes that allow them to ascertain the location of underground utilities from an inaccessible location. This allows them to use electromagnetic (EM) locating to map sewer systems at the same time they’re evaluating them for defects.

What deliverables does GPRS offer when conducting a VPI?

GPRS is proud to offer WinCan reporting to our Video Pipe Inspection clients. Maintaining sewers starts with understanding sewer condition, and WinCan allows GPRS Project Managers to collect detailed, NASSCO-compliant inspection data. GPRS Project Managers not only inspect the interior condition of sewer pipes, laterals, and manholes – they can also provide a map of their location. The GPRS Mapping & Modeling Department can provide detailed GPS overlays and CAD files. Our detailed WinCan/NASSCO reports contain screenshots of the interior condition of the pipe segments that we inspect, as well as a video file for further evaluation, documentation, and/or reference.

Does GPRS offer lateral launch services?

Yes, we offer lateral launch capabilities as part of our standard video pipe inspection services.